From patchwork Thu Sep 6 12:35:26 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 17469 X-Patchwork-Delegate: sw@simonwunderlich.de Return-Path: X-Original-To: patchwork@open-mesh.org Delivered-To: patchwork@open-mesh.org Received: from open-mesh.org (localhost [IPv6:::1]) by open-mesh.org (Postfix) with ESMTP id C057382F45; Thu, 6 Sep 2018 14:35:42 +0200 (CEST) Authentication-Results: open-mesh.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=narfation.org header.i=@narfation.org header.b="zCIVRRj3"; dkim-atps=neutral Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=2001:4d88:2000:7::2; helo=v3-1039.vlinux.de; envelope-from=sven@narfation.org; receiver= Received: from v3-1039.vlinux.de (narfation.org [IPv6:2001:4d88:2000:7::2]) by open-mesh.org (Postfix) with ESMTPS id A532882F43 for ; Thu, 6 Sep 2018 14:35:39 +0200 (CEST) Received: from sven-desktop.home.narfation.org (p200300C593D79FFA9732AEE00057D068.dip0.t-ipconnect.de [IPv6:2003:c5:93d7:9ffa:9732:aee0:57:d068]) by v3-1039.vlinux.de (Postfix) with ESMTPSA id 1BC681100E1; Thu, 6 Sep 2018 14:35:39 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=narfation.org; s=20121; t=1536237339; bh=jth3JGQSwEeN0o3l2tOPLbhKIcwYnKTEfDiYF9FmoXs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zCIVRRj3Q6n3PNHIkOZ3FMWWiKZHB0+xgDL5L6BvsKvYhy4fl3e7GhjSQNZ7nwUlN eMRv0K0gWks5QesAOPiDQyhNgjmT7E2Ww8HwbP3nOEXEC0odiwttMhT0WL2wUWxMxB guK9CPiu2G3mMoetZgrxPk3ChMDy7ZgMGc0Ybacs= From: Sven Eckelmann To: b.a.t.m.a.n@lists.open-mesh.org Date: Thu, 6 Sep 2018 14:35:26 +0200 Message-Id: <20180906123528.30490-4-sven@narfation.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180906123528.30490-1-sven@narfation.org> References: <20180906123528.30490-1-sven@narfation.org> Subject: [B.A.T.M.A.N.] [PATCH v2 3/5] batman-adv: Prevent duplicated softif_vlan entry X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking Errors-To: b.a.t.m.a.n-bounces@lists.open-mesh.org Sender: "B.A.T.M.A.N" The function batadv_softif_vlan_get is responsible for adding new softif_vlan to the softif_vlan_list. It first checks whether the entry already is in the list or not. If it is, then the creation of a new entry is aborted. But the lock for the list is only held when the list is really modified. This could lead to duplicated entries because another context could create an entry with the same key between the check and the list manipulation. The check and the manipulation of the list must therefore be in the same locked code section. Fixes: 952cebb57518 ("batman-adv: add per VLAN interface attribute framework") Signed-off-by: Sven Eckelmann --- v2: * changed batadv_softif_create_vlan to handle problems in batadv_sysfs_add_vlan as fatal error net/batman-adv/soft-interface.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 1485263a..626ddca3 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -574,15 +574,20 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) struct batadv_softif_vlan *vlan; int err; + spin_lock_bh(&bat_priv->softif_vlan_list_lock); + vlan = batadv_softif_vlan_get(bat_priv, vid); if (vlan) { batadv_softif_vlan_put(vlan); + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); return -EEXIST; } vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC); - if (!vlan) + if (!vlan) { + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); return -ENOMEM; + } vlan->bat_priv = bat_priv; vlan->vid = vid; @@ -590,17 +595,23 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) atomic_set(&vlan->ap_isolation, 0); + kref_get(&vlan->refcount); + hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list); + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); + + /* batadv_sysfs_add_vlan cannot be in the spinlock section due to the + * sleeping behavior of the sysfs functions and the fs_reclaim lock + */ err = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan); if (err) { - kfree(vlan); + /* ref for the function */ + batadv_softif_vlan_put(vlan); + + /* ref for the list */ + batadv_softif_vlan_put(vlan); return err; } - spin_lock_bh(&bat_priv->softif_vlan_list_lock); - kref_get(&vlan->refcount); - hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list); - spin_unlock_bh(&bat_priv->softif_vlan_list_lock); - /* add a new TT local entry. This one will be marked with the NOPURGE * flag */